The present invention relates to preparation of pyrazine compounds and/or compositions containing the same.
Pyrazine compositions and derivatives thereof are known to have utility in varieties of applications in various industries as broad-ranging as the pharmaceutical, dyestuff and rubber industries. A plurality of reactant compounds and compositions and reaction mechanisms and conditions have been described, proposed and suggested in the art, including such as those described in U.S. Pat. No. 3,067,199, wherein alkanolamine compounds are disclosed to be reacted with nickel or cobalt hydrogenation/dehydrogenation catalysts at elevated temperature which is said to "favor" pyrazine formation when carried out under sub-atmospheric pressure; in U.S. Pat. No. 3,676,442, wherein acetylene compounds are reacted with an ammoniacal derivative under acid conditions at elevated pressure; in U.S. Pat. No. 4,855,431, wherein pyrazines are prepared by passing an aminoalkyl over a particular crystalline aluminosilicate zeolite composition; and in Japanese Kokai 52-97983, wherein an acyloin compound and an ammonium salt of an acid are heated, as exemplified, with a heat-stable solvent, under neutral or acidic conditions.
As indicated by G. P. Rizzi, in J. Arig. Food Chem. Vol. 36 No. 2, 1988, pp. 349-352, who proceeded to study the nature of pyrazine formation from acyloin compounds and ammonium compounds by reactions which included reflux conditions, although alkyl pyrazines have been widely investigated as trace components in foods, their exact origin remains a mystery.
Rizzi notes that alkyl pyrazines have been found in fermented products, and it also is believed that pyrazine compounds tend to be formed during cooking, roasting, or baking of various foodstuffs and thus have importance as flavor components of such foodstuffs. In particular, it is believed that these compounds impart roast flavor and aromatic characteristics to foodstuffs and also may impart charred notes which are desirable in moderation. Thus, efforts are being made to attempt to prepare such compositions in a food-acceptable manner.
As will be noted from the above-noted art, however, procedures to isolate pyrazine compounds from a reaction mixture are generally complex and, but for one embodiment of U.S. Pat. No. 3,676,442, wherein a filtering and crystallyzation of the desired product is disclosed, that art teaches complex solvent extraction and/or distillation isolation steps.